Organisms in which of the following phyla are triploblastic, acoelomate and have bilateral symmetry?

Consider the following biomes: Tropical Rainforest $(P)$; Tundra $(Q)$; Desert $(R)$ and Coastal zone $(S)$. The most probable order of Net Primary Productivity of these biomes is

Nine percent of a population cannot taste a certain food item because of a recessive allele of the gene IAT. Assuming the population is in Hardy-Weinberg equilibrium, what will be the frequency of dominant and recessive alleles, respectively?

As opposed to DNA replication within the cell, discontinuous synthesis of DNA does NOT occur in a polymerase chain reaction (PCR). Why?